This invention is a method of forming coatings using compositions containing a methyl silsesquioxane resin and colloidal silica as coating for electronic devices.
The use of hydrogen silsesquioxane resin (HSiO.sub.3/2).sub.n derived ceramic coatings on substrates such as electronic devices is known. U.S. Pat. No. 4,756,977 to Haluska et al. discloses a process of forming a silica coating on an electronic substrate by applying to the substrate a solution of hydrogen silsesquioxane resin and thereafter heating the coated substrate in air at a temperature in the range of 200.degree.-1,000.degree. C. However, it is not possible to produce thick planarizing coatings from hydrogen silsesquioxane resins.
The use of hydrolyzed or partially hydrolyzed silicate esters derived ceramic coatings on substrates such as electronic devices is known. U.S. Pat. No. 4,749,631 to Haluska et al. discloses a process for forming a silica coating on an electronic substrate by applying to the substrate a solution of a hydrolyzed or partially hydrolyzed silicate ester and thereafter heating the coated substrate at a temperature in the range of 200.degree. to 1,000.degree. C.
The use of an acidic dispersion of colloidal silica and partial condensate of RSi(OH).sub.3 to produce abrasion resistant coatings is known. U.S. Pat. No. 3,986,997 to Clark describes a coating composition containing an acidic dispersion of colloidal silica, and partial condensate of methylsilanetriol in an alcohol-water medium. The coating composition can be used to apply transparent abrasion resistant coatings on a variety of substrates. However, U.S. Pat. No. 3,986,997 does not teach producing a ceramic or ceramic-like coating from the acidic dispersion or the use of the acidic dispersion to form planarizing coatings on electronic substrates.